546 research outputs found
Effect of aging on endogenous level of 5 alpha-dihydrotestosterone, testosterone, estradiol, and estrone in epithelium and stroma of normal and hyperplastic human prostate.
associated with aging. Thus, the question arises whether or not a
correlation exists between the well known prostatic androgen and
estrogen accumulation and aging. To address this question, we measured
5a-dihydrotestosterone (DHT), testosterone, estradiol, and estrone
in epithelium and stroma of six normal (NPR) and 19 BPH and
correlated the values with the age of the donors (26-87 yr). The mean
DHT level in NPR epithelium was significantly higher than in NPR
stroma, and also significantly higher than in epithelium and stroma of
BPH. The epithelial DHT level of NPR and BPH decreased with age,
the correlation being statistically significant. The stromal DHT level
of NPR and BPH showed no correlation with age. Concerning testosterone,
generally rather low values were found which showed no correlation
with age. The mean levels of estradiol and estrone were
significantly higher in BPH stroma as compared to BPH epithelium
as well as to NPR epithelium and stroma. In NPR, the mean levels of
estradiol and estrone were significantly higher in epithelium than
stroma. In NPR and BPH, the stromal estradiol and estrone levels
increased significantly with age. In epithelium such a correlation between
the estrogen levels and age was not found. Our results indicate
that the prostatic accumulation of DHT, estradiol, and estrone is in
part intimately correlated with aging, leading with increasing age to a
dramatic increase of the estrogen/androgen ratio particularly in stroma
of BPH
Cell adhesion and cell mechanics during zebrafish development
During vertebrate development, gastrulation leads to the formation of three distinct germlayers. In zebrafish a central process is the delamination and the ingression of single cells from a common ancestor tissue - that will lead to the formation of the germlayers. Several molecules have been identified to regulate this process but the precise cellular mechanisms are poorly understood. Differential adhesiveness, a concept first introduced by Steinberg over 40 years ago, has been proposed to represent a key phenomena by which single hypoblast cells separate from the epiblast to form the mesendoderm at later stages. In this work it is shown that differential adhesion among the germlayer progenitor cells alone cannot predict germlayer formation. It is a combination of several mechanical properties such as cell cortex tension, cell adhesion and membrane mechanical properties that influence the migratory behavior of the constituent cells
Nucleon structure with pion mass down to 149 MeV
We present isovector nucleon observables: the axial, tensor, and scalar
charges and the Dirac radius. Using the BMW clover-improved Wilson action and
pion masses as low as 149 MeV, we achieve good control over chiral
extrapolation to the physical point. Our analysis is done using three different
source-sink separations in order to identify excited-state effects, and we make
use of the summation method to reduce their size.Comment: 7 pages, 5 figures. Talk presented at the 30th International
Symposium on Lattice Field Theory (Lattice 2012), June 24-29, 2012, Cairns,
Australi
Nucleon form factors with light Wilson quarks
We present nucleon observables - primarily isovector vector form factors -
from calculations using 2+1 flavors of Wilson quarks. One ensemble is used for
a dedicated high-precision study of excited-state effects using five
source-sink separations between 0.7 and 1.6 fm. We also present results from a
larger set of calculations that include an ensemble with pion mass 149 MeV and
box size 5.6 fm, which nearly eliminates the uncertainty associated with
extrapolation to the physical pion mass. The results show agreement with
experiment for the vector form factors, which occurs only when excited-state
contributions are reduced. Finally, we show results from a subset of ensembles
that have pion mass 254 MeV with varying temporal and spatial box sizes, which
we use for a controlled study of finite-volume effects and a test of the
"" rule of thumb.Comment: 7 pages, 3 figures. Talk presented at the 31st International
Symposium on Lattice Field Theory (Lattice 2013), July 29-August 3, 2013,
Mainz, German
Initial Studies of Isolated Kidney Perfusion
Angiographic and gravametric studies of dog kidneys perfused with electrolyte, Dextran, or albumin solution are presented to demonstrate the possibility of extending organ preservation for transplantation without loss of function. Findings include a reduction in flow and weight gain with the nonprotein solutions and maintenance of flow with albumin solution. Gross changes of the perfused kidneys are also described
Computing the nucleon charge and axial radii directly at in lattice QCD
We describe a procedure for extracting momentum derivatives of nucleon matrix
elements on the lattice directly at . This is based on the Rome method
for computing momentum derivatives of quark propagators. We apply this
procedure to extract the nucleon isovector magnetic moment and charge radius as
well as the isovector induced pseudoscalar form factor at and the axial
radius. For comparison, we also determine these quantities with the traditional
approach of computing the corresponding form factors, i.e. and
for the case of the vector current and and
for the axial current, at multiple values followed by
-expansion fits. We perform our calculations at the physical pion mass using
a 2HEX-smeared Wilson-clover action. To control the effects of excited-state
contamination, the calculations were done at three source-sink separations and
the summation method was used. The derivative method produces results
consistent with those from the traditional approach but with larger statistical
uncertainties especially for the isovector charge and axial radii.Comment: 16 pages, 7 figure
High-precision calculation of the strange nucleon electromagnetic form factors
We report a direct lattice QCD calculation of the strange nucleon
electromagnetic form factors and in the kinematic range . For the first time, both and
are shown to be nonzero with high significance. This work uses
closer-to-physical lattice parameters than previous calculations, and achieves
an unprecedented statistical precision by implementing a recently proposed
variance reduction technique called hierarchical probing. We perform
model-independent fits of the form factor shapes using the -expansion and
determine the strange electric and magnetic radii and magnetic moment. We
compare our results to parity-violating electron-proton scattering data and to
other theoretical studies.Comment: 6 pages, 5 figures. v2: references adde
Direct force measurements of subcellular mechanics in confinement using optical tweezers
During the development of a multicellular organism, a single fertilized cell divides and gives rise to multiple tissues with diverse functions. Tissue morphogenesis goes in hand with molecular and structural changes at the single cell level that result in variations of subcellular mechanical properties. As a consequence, even within the same cell, different organelles and compartments resist differently to mechanical stresses; and mechanotransduction pathways can actively regulate their mechanical properties. The ability of a cell to adapt to the microenvironment of the tissue niche thus is in part due to the ability to sense and respond to mechanical stresses. We recently proposed a new mechanosensation paradigm in which nuclear deformation and positioning enables a cell to gauge the physical 3D environment and endows the cell with a sense of proprioception to decode changes in cell shape. In this article, we describe a new method to measure the forces and material properties that shape the cell nucleus inside living cells, exemplified on adherent cells and mechanically confined cells. The measurements can be performed non-invasively with optical traps inside cells, and the forces are directly accessible through calibration-free detection of light momentum. This allows measuring the mechanics of the nucleus independently from cell surface deformations and allowing dissection of exteroceptive and interoceptive mechanotransduction pathways. Importantly, the trapping experiment can be combined with optical microscopy to investigate the cellular response and subcellular dynamics using fluorescence imaging of the cytoskeleton, calcium ions, or nuclear morphology. The presented method is straightforward to apply, compatible with commercial solutions for force measurements, and can easily be extended to investigate the mechanics of other subcellular compartments, e.g., mitochondria, stress-fibers, and endosomes.MK acknowledges financial support from the Spanish Ministry of Economy and Competitiveness through the Plan Nacional (PGC2018-097882-A-I00), FEDER (EQC2018-005048-P), Severo Ochoa program for Centres of Excellence in R&D (CEX2019-000910-S; RYC-2016-21062), from Fundació Privada Cellex, Fundació Mir-Puig, and from Generalitat de Catalunya through the CERCA and Research program (2017 SGR 1012), in addition to funding through ERC (MechanoSystems) and HFSP (CDA00023/2018). V.R. acknowledges support from the Spanish Ministry of Science and Innovation to the EMBL partnership, the Centro de Excelencia Severo Ochoa, MINECO's Plan Nacional (BFU2017-86296-P, PID2020-117011GB-I00) and Generalitat de Catalunya (CERCA). V.V. acknowledges support from the ICFOstepstone PhD Programme funded by the European Union's Horizon 2020 research and innovation program under Marie Skłodowska-Curie grant agreement 665884Peer ReviewedPostprint (published version
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